Macintosh LC Restoration Video Series

[Ferrix97]

Hello!

A friend of mine brought me a few Mac LCs and LC IIs to restore, this time I decided to record most of the electronics restoration, here I am replacing the ELNA Capacitors inside the PSU (with a bit of rambling on it)

Hopefully you will find the video entertaining and maybe useful.

Soon I will upload the Logic board Cleaning and ReCap, I think it will take Days to upload, but I should compress it.

Let me know what you think!

I'm doing this just to be useful, sometimes i've seen peoples asking for specific videos, but there aren't many on the net, I am not doing this to gain views or to make money!

 

[Elfen]

Excellent video.

If anything, do the washing and recapping as separate videos. Saves time and space at the same time.

 

[techknight]

Need to change ALL the caps. not just those few. Nevertheless, glad it works

 

[Elfen]

According to Uniserver, it is the ENLA capacitors in the LC Series Power supply that always fails, while the other caps seem to remain rock solid. And he is not the only reference I have seen on this. It is these (4) caps that Ferrix97 replaced.

Here's Uniserver's page on the LC power supply: http://maccaps.com/MacCaps/Capacitor_Reference/Entries/1990/10/15_LC_I%2C_II%2C_III_Power_Supplies.html

 

[techknight]

Doesn't matter. They are all of the same age. And were subject to all of the same stresses. 

So what your saying is, when I recap a tube type radio, or more likely, modern televisions, I only replace a few known suspect capacitors? Wrong... Try that with a Mitsubishi V26 DLP Chassis and see how far that gets ya. Change them all. When they are all that age, they all need changed. 

Granted some capacitors are of higher quality and last longer than others, I dont recommend leaving them behind. Same deal with vintage 70s/80s stereo gear, I recap it all. Sounds awesome and like brand new. 

 

[techknight]

I deal with this all the time in the car audio industry, bad main rail capacitors. Might have 1 or 2 blown. But they all need replaced. Changing just the bad ones, results in the rest of them blowing and the amplifier comes right back to you for further repair. 

Matter of fact, I have seen a few where other people have replaced only one or two caps. And the rest of them failed.  Now granted car audio equipment are in very different environments, and they are pushed much harder than most common computer stuff. But the concept still applies, its all electronics and they all do the same thing in the end. 

 

[Elfen]

I see your point and agree Techknight. But I remember an espionage case from the 1990s which affects computers today. This case involves capacitors, where a mole in a USA Electronics  firm stole the designs for a more efficient cap and sold it to the Chinese where they started to flow the market with these caps. Problem is, the mole only got 1/2 the design and the Chinese caps would leak within months of use. Years later the same thing happen to a Japanese Electronics Firm where another cap design was stolen and sold to the Chinese where they flooded the PC Manufacturers with these caps with more disastrous results - blow up on the motherboards after 6 months or so of use. Once again, it was only a partial design plan that was stolen.

The market is still flooded with these bad caps, and people like Uniserver managed to get a name for one of them, ENLA as used by Apple and other PC manufacturers. I'm sure that the Audio market has these bad caps too. But there are many good caps out there, lasting 20+ years. My Sansui Amp is from the 1970s and its still going strong with no issues with its caps, though I did had to replace a couple of final transistors in the past. My Blaupunk Car stereo which I had with my first car in 1981, has went from car to car to car is still going strong. As is my Cobra 148 CB Radio, with so many mods on it I can not post them but it is modded to push out 12 watts instead of 5, has not shown any problems with caps and I had it since 1986. As far as my ancient computers are concerned, my Commodore Vic20 and C64 are going strong as is my Apple II/IICs and Laser 128.

I want to see what Uniserver has to say on these repaired power supplies and how long they lasted with just a few caps replaced.

 

[Ferrix97]

Well, I also shot a video about heating a TDK PSU with a hair dryer, on that one I replaced the ELNA ones, but the output were too low, once I heated it up, it started woking again, this means that not only the ELNA ones were faulty (before replacing them it was just ticking, 0 on the outputs) but the Nichicon ones are faulty too!

 

[techknight]

Yea I am aware of that epidemic. But that really didnt start plauging us until about the late 1990s to early 2000s or so. And they were mostly CapXon, etc... Nichicon did have a bad batch but that was only for a couple years. 

We are talking late 80s early 90s stuff here, which would have been unaffected by this. 

Also how the cap leaks depends on manufacturing process and how they are used, and stored. they are only rated for a finite lifetime of a certain temperature range. the graphs are available. 

ELNA isnt the only, and actually aside from united chemicon, and panasonic, ELNA was one of the best caps to have. Audio equipment from the 70s/80s were FILLED with ELNA caps. 

The thing with elna capacitors, back then they really werent rated for low-esr which is critical in switching power supply applications. So of course they died. I had to change a shitload of elna and nichicon capacitors in an 80s fax machine once, they were ALL bad. and this was 2002. 

 

[Ferrix97]

The fault might be generated also by the environment where the computer was stored, i know that the previous owner stored it in a very hot attic, and it may have gone very cold in winter too.

I think that the environment where the computer was stored affected the life of the capacitor

 

[Ferrix97]

Finally uploaded the Logic board restoration, enjoy!